One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,5,7,8)(9,10)(11,14)(12,17)(13,16)(15,20)(18,22)(19,24)(21,23)(25,26)(27,31)(28,36)(29,34)(30,32)(33,38)(35,40)(37,39)(1,2)(3,5)(4,6)(7,8)(9,10,14,11)(12,15,20,17)(13,16,22,18)(19,23,21,24)(25,27,30,29)(26,31,32,34)(28,35,38,37)(33,39,36,40)(10,11)(15,17)(16,18)(23,24)(26,32)(31,34)(33,36)(39,40) involution — undirected(1,3,4,7)(2,5,6,8)(9,11,14,10)(12,17,20,15)(13,18,22,16)(19,24,21,23)(25,26)(27,31)(28,33)(29,34)(30,32)(35,39)(36,38)(37,40)(9,12)(10,15)(11,17)(13,21)(14,20)(16,24)(18,23)(19,22)(25,28)(26,33)(27,35)(29,37)(30,38)(31,39)(32,36)(34,40) involution — undirected(9,13,14,22)(10,16,11,18)(12,19,20,21)(15,23,17,24)(25,29,30,27)(26,34,32,31)(28,37,38,35)(33,40,36,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.